1. Field of the Invention
The invention relates to the herbicidal use of 5-propionylamino-3-methylisothiazole against weeds, primarily, broadleaf weeds
2. Description of the Prior Art
Robba and Moreau, in Annales pharmaceutique francaises, 22, 1964, No. 3, pages 201-210, describe 5-propionylamino-3-methylisothiazole as a derivative formed from 5-amino-3-methylisothiazole, (a compound described by Adam et al in U.S. Pat. No. 2,871,243) and propionyl chloride, which they nitrated at the 4 position of the isothiazole ring, to form the derivative 5-propionylamino-4-nitro-3-methylisothiazole. This derivative was inactive against Trichononos vaginalis, a pathogen causing infections of the human vagina. Stock et al, in U.S. 2,871,243, describe the starting material, 5-amino-3-methylisothiazole, as an intermediate to the derivative 5-(p-acetamidobenzenesulphonylamino)-3-methylisothiazole, a useful bactericide for Escherichia coli. Other workers, in the Journal of the Chemical Society, 1959, pages 3061 to 3071, describe the acetyl, dichloroacetyl and benzoyl derivatives of the 3-amino-5-methylisothiazole but give no uses for them. The chloroacetyl derivative, an analgesic, is listed in Volume 59 of Chemical Abstracts, Column 2791 (1963). Stock et al, in U.S. 3,186,999, describe semi-carbazone, and thiocarbazone derivatives of 5-amino-3-methylisothiazole, which are active against pox viruses. In Japanese patent 5641/64, S. Kamio et al (Chemical Abstract 59, column 2791a) describe monohalogenocarboxylic amides of isothiazole as useful intermediates for amino-carboxylic acid derivatives.
Others describe certain specified cyanated, halogenated, benzoated, or urea-substituted isothiazole derivatives as herbicides for certain weeds or fungicides for certain fungi in U.S. Pat. Nos. 3,155,678, 3,393,992, 3,454,591, 3,541,108, 3,564,985, 3,622,593, and 3,692,795. None of the above-mentioned references describe or suggest that a simple acylamino derivative of 3-methylisothiazole, such as 5-propionylamino-3-methylisothiazole, has herbicidal usage particularly against broadleaf weeds.